Known particle separators function to form a particle containing liquid into a small diameter jet stream and then break the jet stream into particle containing droplets. The droplet formation is guided by vibration energy applied to the separator. See, for example, U.S. Pat. No. 4,302,166, granted Nov. 24, 1981, to Mack J. Fulwyler and C. W. William Hatcher, and U.S. Pat. No. 4,361,400, granted Nov. 30, 1982, to Joe W. Gray, Terry W. Alger and David E. Lord.
It is important that the vibration be at a precise, stable frequency. Since the vibration energy determines the break-off point of the droplets, it is important that the energy be constant. In current practice, the vibration frequency is determined by an electronic oscillator that drives a piezo electric element that is incorporated into the separator. There is a need to provide the vibration energy in a way that does not require use of an electronic oscillator because electronic oscillators are expensive. Further, the known apparatuses for forming the droplets have to be cleaned and sterilized between uses. There is a need for a droplet forming apparatus in which at least some of the components that are contacted by the carrier liquid are disposable so that the need to clean and sterilize is significantly reduced, if not eliminated.
It is an object of the present invention to provide a particle separator that is simple, yet durable, inexpensive to make and use, and which includes a mechanical oscillator driven by a piezo electric element to provide substantially constant vibration energy to a nozzle. Another object is to provide a particle separator in which components that are contacted by the particle containing liquid are disposable, so as to at least reduce the need to clean and sterilize between uses. A further object of the invention is to provide a method of droplet formation by use of a mechanical oscillator and components in contact with the particle carrying liquid that are disposable. Yet another object of the invention is to provide a particle separator that is adapted to monitor the vibration energy existing in the particle separator.
Additional prior art particle separators and particle separating methods, present in the patent literature, are disclosed by: U.S. Pat. No. 3,963,606, granted Jun. 15, 1976 to Walter R. Hogg; U.S. Pat. No. 4,325,483, granted Apr. 20, 1982 to Igino Lombardo, Donald E. Barry and W. Peter Hansen; U.S. Pat. No. 5,007,732, granted Apr. 16, 1991, to Hiroshi Ohki, Hideaki Kamohara and Ryo Miyake; U.S. Pat. No. 5,079,959, granted Jan. 14, 1992, to Ryo Miake, Hiroshi Ohki, Isao Yarnazaki, Toshio Kaneko, Hideyuki Horiuchi, Shinich Sakuraba, and Kaori Yasuda; and U.S. Pat. No. 4,538,733, granted Sep. 3, 1985, to Michael A. Hoffman. These patents and the two earlier mentioned patents should be carefully considered for the purpose of putting the subject invention into proper perspective relative to the prior art.